Beverage dispensers generally combine measured ratios and/or amounts of various fluids so as to produce a desired beverage. These fluids generally can be described as micro-ingredients, macro-ingredients, and diluents. Micro-ingredients generally have high reconstitution ratios while macro-ingredients are added either at full strength or at low reconstitution ratios, typically in the range of about 1 to 1 to about 6 to 1 with respect to the diluent. Macro-ingredients have a wide range of viscosities, in the range of 1 to 10,000 centipoise. Macro-ingredients include fruit juices, concentrated extracts, dairy products, sugar syrup, high fructose corn syrup, and similar types of ingredients.
In order to detect abnormal operation, a beverage dispenser may have a number of beverage pumps in communication with a number of flow sensors so as to provide feedback and to detect “no flow” events such as sold out packages or blocked lines. The flow sensors used with macro-ingredient pumps need to accommodate the wide range of viscosities described above. Known flow sensors, however, typically work in a narrow range of viscosities.
There is a desire, therefore, for an improved flow sensor that can accommodate varying viscosities. The flow sensor should be reliable, provide adequate feedback, and be easy to clean.